SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06b3e4a2e6ea8546bd10255a45a06ccffc972c5cbe9820586faa630d210527cc' 
  AND token = 'PKZbuNdlgdtGWq1i9IbEbxOtbL4E3zdbaB3vBQfnDhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}